"In my life and all the careers of any Black singer, female Black singer, she is monumental," said Moore. "She paved the way."
Anderson, who was born in Philadelphia, sang that song on the steps of the Lincoln Memorial 85 years ago.
It was after she was denied the stage at Constitution Hall because of her race.
"I always think I cannot imagine what it was like for her to have that conflict," said Jennifer DePreist, Anderson's great-niece. "To summon all of her courage at that moment to perform this one voice out in front of 75,000 people. It's just extraordinary."
On Saturday night, DePreist along with hundreds of people gathered at the Kimmel Center for the Great Stages Concert hosted by Queen Latifah to honor Anderson.
Earlier in the day, the Philadelphia Orchestra and Ensemble Arts officially rededicated Verizon Hall as Marian Anderson Hall.
"To be able to honor her with what I think is the first major hall to bear her name is a momentous act," said Matias Tarnopolsky, the Philadelphia Orchestra and Ensemble Arts President and CEO. "It's not just about Philadelphia, it has global consequences."
"We want everybody to truly understand the arts are for everyone, the stages are for everyone and the person who made that possible is Marian Anderson," said Katharine Schimmer, the Philadelphia Orchestra and Ensemble Arts strategic initiatives director.
They hope people use their power to make positive change, like Anderson did.
"We've done a lot of work since she performed, but there is still work to be done and just continuing to celebrate the whole continuum of people like her," said Isabella DePreist-Sullivan, another of Anderson's relatives.
"To have a legacy preserved in this way is absolutely wonderful, and it can inspire so many young people here," said DePreist. "It can inspire people who come to visit Philadelphia as tourists because it's a world city."
State representatives also announced June 8 as Marian Anderson Day in Pennsylvania to honor the worldwide pioneer.